Palestinians wait to travel to Egypt through the Rafah border crossing on Friday.
Photograph: Said Khatib/AFP/Getty Images

The UN’s senior human rights official has castigated Israel, saying there is little evidence that its armed forces attempted to minimise casualties during protests by Palestinians this week during which dozens of demonstrators were killed.

As a special session of the UN human rights council voted to set up a commission of inquiry to look into Monday’s violence, Zeid Ra’ad al-Hussein said that while 60 Palestinians were killed and thousands injured in the day of protests, “on the Israeli side, one soldier was reportedly wounded, slightly, by a stone.”

He told the council on Friday: “The stark contrast in casualties on both sides is … suggestive of a wholly disproportionate response.”

Egypt’s president, Abdel-Fatah al-Sisi, announced he had ordered the opening of the Rafah border crossing with Gaza for the whole of the Muslim holy month of Ramadan, the longest period of access since 2013.

He wrote on his official Twitter account late on Thursday that the opening would “alleviate the burdens of the brothers in the Gaza Strip”.

The Rafah crossing is Gaza’s main gate to the outside world. Egypt has kept Rafah largely sealed off since 2013, when the elected president Mohamed Morsi was removed from power.

On Friday travellers were slowly moving towards the crossing. A bus arrived about every hour carrying people whose names appeared on lists provided by Hamas officials, who oversee who goes through the border.

Hussein told the UN meeting in Geneva that many of the Palestinians injured and killed in the protests “were completely unarmed [and] were shot in the back, in the chest, in the head and limbs with live ammunition.” He said there was “little evidence of any [Israeli] attempt to minimise casualties”.

“Although some of the demonstrators threw molotov cocktails, used slingshots to throw stones, flew burning kites into Israel and attempted to use wire-cutters against the two fences between Gaza and Israel, these actions alone do not appear to constitute the imminent threat to life or deadly injury which could justify the use of lethal force,” he said.

The council voted 29-2 with 14 abstentions to set up a commission of inquiry and back a resolution condemning “the disproportionate and indiscriminate use of force by the Israeli occupying forces against Palestinian civilians”.

Israel’s ambassador to the UN, Aviva Raz Shechter, said her country tried to minimise casualties when it defended its borders against “terrorists” in Gaza. She accused Hamas militants of using human shields, and accused the council of indulging in the “worst form of anti-Israel obsession”.

She said: “This special session, the resolution before you and its call for a commission of inquiry are yet again politically motivated and won’t change the situation on the ground by even one iota.”

The commission of inquiry will be asked to produce a final report by next March.

Israel has long argued that Hamas hides behind the civilian population in Gaza, as an explanation for the high casualty rates among non-combatants. It pounced on a claim by a Hamas official that 50 of the 60 people killed on Monday were associated with the group.

Critics, including Israeli human rights lawyers and activists, say Israel’s use of lethal force rather than possible alternatives is a clear violation of human rights law.

“Let me put it in a soundbite,” Michael Sfard, a lawyer, told Slate after Monday’s killings. “International law allows endangering human life in order to protect human life, not any other thing. And what we are seeing here is a deviation from that very simple, very important principle.”

During six weeks of mass protests and violence along the Gaza border, Palestinian refugees have been demanding the right to return to their homes inside what is now Israel.